UV curable adhesives are a modern adhesive technology that offers many advantages. We at artimelt can look back on more than 20 years of experience in the development of radiation curable UV adhesives and are happy to pass on our artimelt knowledge to you for the switch to UV technology. This artimelt blog is intended to help processors of adhesives make the decision to switch to UV technology.

Change from rubber-based hot melt to UV-curable adhesives

artimelt assumes that, up to this point, you have been processing classic rubber-based hot melt. In this case the step to UV curable adhesives is a small one. You will already be familiar with hot melt, know how it is processed and have the appropriate equipment, such as a barrel melter, buffer tank and a coating plant in-house. You will also be familiar with the advantages and disadvantages of rubber-based hot melt, such as easy processing, good adhesion at low temperatures, or low weather resistance or temperature resistance. The first question to be answered now is whether you need the positive properties of UV curable adhesives for your products, such as:

• High temperature resistance up to 200°C
• High chemical resistance
• High UV resistance and therefore suitable for outdoor applications
• Approval for direct food contact
• Good punching properties

artimelt UV adhesives fulfill all these positive properties. In close cooperation, artimelt develops tailor-made UV adhesives for you, which are perfectly suited to your processing possibilities and fields of application.

Upgrade your coating systems with UV lamps

You can continue to use your existing coating system, but you will have to “upgrade” it. artimelt recommends the following: Talk to a UV equipment manufacturer and tell them what you want to do. Tell him you need UV lamps that emit in the UVC range so that artimelt adhesives can be cross-linked. Also consider the following points:

• How wide is my system?
• At what speed do I want to operate my system?
• How high is the coating weight going to be?
• How much space do I have on my existing hot melt system for UV lamp installation?
• Would I like to have the latest measurement and control technology that measures the UV output during system operation and adjusts it to the target value, or would I like to check and readjust it manually?

All these points ultimately have an influence on the entirety of the equipment and thus also on your investment costs.

Invest for the future: more UV lamps, separate barrel melting units, buffer tank and hose lines

A very important artimelt tip: Don't just have the UV system designed to meet your current needs. Think about the future and invest in more lamp units than you need today. This has the following advantages:

• You can coat a higher coating weight and network safely.
• You can increase the coating speed.
• If the existing lamp fails, you can switch on the spare lamp and continue production.

artimelt also recommends investing in separate barrel melting units, buffer tanks and hose lines to the application head. UV curable adhesives are not compatible with other hot melt systems and can lead to gel formation when mixed, resulting in a poor coating appearance.

With this additional equipment you can kill several birds with one stone:

• You can very quickly switch from classic hot melt to UV adhesives.
• You will save yourself the time-consuming cleaning of barrel melter, buffer tank and hose lines every time the adhesive is changed.
• You will avoid the risk of gel formation.

Summary

artimelt has summarized the most important points for you:

• First answer the question whether you need the properties of the UV adhesives.
• You will need lamps that emit in the UVC range.
• Think about the future and invest in more lamp units than you need today.
• Invest in additional peripheral equipment such as a barrel melter, buffer tank and hose lines.

artimelt has comprehensive know-how regarding UV adhesives and the best contacts to equipment manufacturers. Let your artimelt Key Account Manager advise you.

A large number of medical products are packaged and sterilized, including plasters, medical tape, surgery drapes and ECG electrodes. All of these products use an adhesive. The packaging is also often closed or sealed with an adhesive. The adhesive must be able to withstand the sterilization processes commonly used without its properties changing. Furthermore, the sterile properties of the product must remain the same over a long period of time.

There is a difference between adhesives that form direct bonds on the skin and those that are used as laminating adhesives and do not come into direct contact with human skin. Adhesives that are allowed to come into direct contact with skin are used in the manufacture of plasters, such as artimelt M11.1506, which is ideal for contact with sensitive skin. Surgery drapes are often made up of multiple layers. The individual layers are stuck together using a laminating adhesive such as artimelt M12.317. Sometimes, a self-adhesive edge strip is applied to ensure that the drape can be affixed to the patient’s skin. artimelt M11.1566 is very well suited for this purpose.

Laminating adhesives are also used in the manufacture of ECG electrodes in order to ensure that the individual components remain reliably and constantly stuck together. At room temperature, these adhesives are dry and non-sticky. However, once they are warmed up, they become soft and their adhesive properties are awakened. The adhesive subsequently forms a bond to the substrate when pressure is applied. These adhesives are different from pressure-sensitive adhesives (PSA) that are constantly sticky and must be covered with a release liner.

During the sterilization process, the question of “what happens to the adhesive?!” is always asked. Does the form, color, smell, etc. of the adhesive change? artimelt carried out a comprehensive study and subjected selected artimelt adhesives to individual sterilization methods:

• Ethylene oxide sterilization (EtO)
• Gamma radiation
• X-ray radiation

The results from the investigation into artimelt M11.1566 – an adhesive for plasters and tapes – are listed as an example.

Extract from the results for the artimelt M11.1566 adhesive

The chart shows the change in the adhesion and cohesion values following sterilization.

The “0-value” values show the adhesive properties prior to sterilization. Depending on the method used, barely any differences were recorded. This means that the adhesive almost retains its original properties. The sterilization process can even be said to have positive effects on the adhesive, as the cohesion – and therefore the internal strength – increase and the adhesion remains the same! Based on this study, we can say that the artimelt adhesives are ideally suited for sterilization.

artimelt adhesives

In addition to high-quality raw materials, extensive specialist knowledge is also required to manufacture premium products for medical applications. artimelt has over 30 years’ experience in the development and manufacture of adhesives for medical applications. artimelt adhesives form a secure bond and can still be removed from human skin without causing any pain or leaving any residue behind. In addition, the special formulations are breathable and thus prevent the skin from macerating. It comes as no surprise that artimelt adhesives are tested for their suitability for coming into contact with human skin and are classified as being harmless.

artimelt meets the high standards demanded in the heavily regulated market for medical and sterile applications. We also offer the right products for related markets in which there are high safety standards, such as in the foodstuffs and cosmetics industries. artimelt customers are not only able to choose products from the existing range – artimelt can work in close coordination with customers to develop tailor-made adhesive solutions that are a perfect fit with their processing methods and fields of application.

If you have any questions related to adhesives for use in a sterile environment, please do not hesitate to contact us. The artimelt team would be delighted to hear from you.

Plasters are found in virtually every home first-aid kit. They are available in all shapes and colors and in many different materials, such as fabrics or synthetics. Some plasters have a strong bond and some can be removed easily, while others have additional functions such as antibacterial properties, padding, absorption of wound secretions or for administering medication. What is clear is that the demands on modern plasters have increased. Below, you can find a summary of the most important requirements.

Skin

All of these different plasters are affixed to the skin, which is the largest organ in the human body. The skin is a very special surface when it comes to attaching things to it. On an adult human, the total surface area is around 1.7 m² and total weight between 10 and 14 kg. It consists of several different layers, with the epidermis the outermost layer. The skin has a range of different functions, including the exchange of substances. In other words, substances are both absorbed and emitted to different degrees through the body surface. A typical example here is perspiration during sport. The sweat glands produce sweat in order to prevent the body from overheating. The skin is also a very individual organ and behaves differently depending on the age of the person, the climate in which they live and their habits. It can thus be the case that an adhesive for a plaster works perfectly in Europe, but the bond is too strong in Asia and leads to skin irritation when the plaster is removed.

Substrate

The substrate used also plays a significant role in the overall performance of a plaster. Depending on the application, the substrate can be up to 50% responsible for whether the end product ultimately has the desired properties or not. As a result, we recommend carrying out a screening process for those substrates that come into question early on in the development phase. Trial coatings at the laboratory can be a good indicator as to whether the adhesive strength is sufficient or whether the adhesive and substrate are compatible with one another.

Adhesion

Adhesion varies greatly depending on the intended application and target group. For example, surgical drapes that are affixed to the patient or operating table require a different product compared to eye plasters for children. The application weight and coating pattern are other variables that have an effect on adhesion. In most applications, an application weight of between 25 and 40 gsm is sufficient. Full-surface coating is also made in the majority of cases. This is not a significant problem in short-term applications. As before, rubber-based adhesives are most commonly used. These have no moisture vapor permeability, which can lead to maceration of the skin. When using rubber-based adhesives, this can be minimized by applying the adhesive freely, for example in dots or strips.

UV-curing adhesive systems

A more elegant method is to use UV-curing adhesives instead. These systems have a significantly higher moisture vapor permeability, meaning the skin function is not restricted. While human skin has a moisture vapor permeability of around 200 to 400 g/m²/day, artimelt UV-curing adhesives have a moisture vapor transmission rate (MVTR) of 800 to 1,200 g/m²/day. These adhesive types can thus also be used for products in long-term applications. UV-curing adhesives also have other advantages. For example, they have better shear strength compared to traditional rubber products. This means that the products are also more suitable for applications where the patient is active. The water resistance is also higher, meaning the patient can take showers without the plaster losing its adhesive bond and falling off. The high MVTR also helps in this regard. Sweat can be transported away from the body and does not collect between the adhesive and skin, which also leads to a loss of adhesion.

Conclusion

To conclude, one can say that it is an advantage to know both the exact application and the main target group. Both of these factors provide important advance information on which materials should be used. This applies both to the substrate and the selection of the adhesive.

The artimelt team has many years of experience in this field and would be happy to help you find a suitable solution. Thanks to our comprehensive product portfolio and experience with the most diverse substrates, we can work together to find the right combination in order to meet all your product demands.

Introduction

What is the MDR?

The new European MDR replaces the existing MDD (Medical Device Directive) and AIMD (Active Implantable Medical Devices), which will now be combined in the MDR in future.

The advantage of the regulation is that the same aspects apply uniformly for all EU member states. In the two former directives, these had to be implemented in local law. This in turn led to differing assessments in the individual countries.

The goal of the MDR is to increase product safety for patients, which is at the heart of the whole regulation. Transparency should also be increased. A central database (EUDAMED) will be established, where everyone (including private individuals) can obtain information on every medical product approved in the EU.

Changes compared to the MDD

There are several changes in different areas. Four of the most important ones are detailed below.

Expanded scope of application

The AIMDs are now also regulated in the MDR. Moreover, products that do not necessarily have a medical use are also covered by the MDR. Examples here include cosmetic contact lenses, lasers for tattoo removal and implants for body modification.

Classification

The MDR now includes 22 rules for classifying medical products. In the MDD, there were only 18. This is one of the reasons why each medical product has to be newly assessed and classified.

The rules are divided up as follows:

Clinical evaluation of medical products

The requirements for the clinical data required for approval of a medical product are now more stringent. The MDR also describes in more detail which quality the data should have for the clinical assessment. The goal of this is to prove that the claimed effectiveness also exists in practice. Moreover, it should also be possible to exclude any unexpected or unacceptable side effects.

Market surveillance

Post market surveillance (PMS) is now more important than was previously the case. The data obtained in this way must also be incorporated in the clinical assessment of the products, which is then updated accordingly. It is also not sufficient to only monitor one’s own products. Comparable products from competitors also have to be included in PMS. If incidents occur, consideration must be given as to whether measures also have to be taken for own products.

Timeline

How is artimelt dealing with the MDR

With this in mind, artimelt has also kept up to date with the MDR and its consequences via various seminars and through service providers. We are thus well aware of the importance of the MDR for our customers in the medical branch and are prepared to support them as much as we can and share what we know about the MDR.

artimelt has created its own database for products and raw materials in order to maintain an organized and easy to manage overview of the situation. This database should cover the different requirements of the various regulations, whether REACH, MDR, California Proposition 65 or individual queries such as the absence of heavy metals or other critical substances.

Furthermore, artimelt is also committed to making available as much data on biocompatibility as is necessary. This simplifies the creation of technical documentation in diverse product classes and is a good starting point for creating a clinical assessment of your medical product.

We are keeping our eye on the ball here, and are looking forward to sharing information on the MDR and how we can master these challenges together.

Adhesive for direct skin contact
When developing an adhesive that comes into direct contact with the skin, there are always many factors to consider – ones which also need to be coordinated with each other. For example, if a medical device is developed that is affixed to sensitive skin – as can be the case with newborn babies or older people – there are further special requirements when it comes to the adhesive. On one hand, the developed adhesive must be strong enough to remain attached to the skin during the required application period. On the other hand, it must also be possible to remove the medical device painlessly and without damaging the skin after it has been worn.

Properties of the skin and what to pay attention to
Let’s first take a look at the substrate onto which the adhesive is attached in more detail.

Human skin varies from person to person – you will never find the same skin twice.

Factors that affect the skin:

• age
• gender
• diet
• perspiration levels
• geographical factors
• person’s general health

It’s clear that human skin is a very demanding substrate. In order to develop an adhesive that won’t damage sensitive skin when removed, artimelt broke new ground. With artimeltlowpeel, we have developed a product line that has the right properties for ensuring that something as simple as removing a plaster is painless. Patients suffering from chronic wounds will also benefit in future from lower stress on the skin caused by regular dressing changes. With artimeltlowpeel, intact skin is not damaged and no skin trauma is caused.

Typical applications for artimeltlowpeel

• catheter fixations
• eye plasters for children
• applications in the sacral area, treating pressure sores or for fixing dressings in place when treating chronic wounds
• suitable for use with wearables

Due to the many applications, you have probably already guessed that this spectrum cannot be covered by a single adhesive type. artimeltlowpeel consists of a wide variety of products with different properties. The term “low peel” has not yet been uniformly defined, which is why artimelt has taken the step of making our own classification. Adhesives that are suitable for the applications described above have a peel value of < 1 N/25 mm and a loop tack of < 5 N/25 mm. These values are measured against steel and cannot be compared to human skin. Therefore, in order to ensure that the individual adhesives can be compared, we have thus used steel as a reproducible substrate when gathering the technical data. As skin differs from person to person, you would get different values each time in this case.

Depending on the application and patient group, it also makes sense to test an adhesive with higher peel values. However, a peel value of 10 N/25 mm should not be exceeded, otherwise the desired low-peel effect is lost despite the adhesive properties.

How is this low-peel effect achieved?
The adhesive formulation is one aspect, of course. We use a new thermoplastic acrylate as base material. One advantage of this raw material is that we are then not dependent on UV radiation, which is the case for UV-curing adhesives. Another advantage of this thermoplastic acrylate is that it is breathable. This means that it is also suitable for applications where a plaster or wearable should be applied for a longer period. This is because maceration – the softening and breaking down of skin resulting from prolonged exposure to moisture – does not take place.

Application weight
The second key aspect is the application weight. A coat weight between 100 and 200 grams per square meter is recommended. Thanks to this high coat weight, the effect between cohesion of the adhesive and adhesion between the adhesive and skin becomes apparent. Thanks to the interplay between cohesion and adhesion, a product is created that has this low-peel effect and can thus also be gently removed from the skin.

Antibacterial protection
In order to further expand the entire range, we are already planning the next steps. In addition to gentle removal, the artimeltlowpeel line should also be equipped with other properties such as antibacterial protection.

If you require more information on artimeltlowpeel, our adhesive experts would be happy to help.